Rotary engine



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Feb. 2, 1960 H. A. DE LANEY 2,923,251.

v ROTARY ENGINE Filed April 2, 1956 2 Sheets-Sheet 1 www4-AH ATTORNEYSFeb. 2, 1960 H. A. DE LANEY y 2,923,251

ROTARY ENGINE ATTORNEYS United States Patent ROTARY ENGINE Howard A. DeLaney, Watertown, N.Y., assignor to The JNew York Air Brake Company, acorporation of New ersey Application April 2, 1956, Serial No. 575,400

3 Claims. (Cl. 103-173) This invention relates to rotary hydraulicengines. Specifically it relates to an improvement to the enginedescribed and claimed in the Huber patent, No. 2,391,- 575, datedDecember 25, 1945, and assigned to applicants assignee.

The structure of the engine in a preferred embodiment of the presentinvention is basically similar to that shown in the Huber patent. Theengine comprises a multipart housing having a centrally located cylinderblock secured therein. The cylinder block is provided with a circularseries of through cylinder bores which are parallel with one another andwith the axis of a rotary shaft Which extends through central bearingsformed in the cylinder block. The axial position of the shaft isdetermined by adjustment of a screw threaded abutment in one end of thehousing. This feature of the preferred embodiment is more fullydescribed and claimed in theapplication of M. W. Huber, Serial No.576,670, le April 6, 1956, and now Patent No. 2,785,639, dated March 19,1957, andassigned to applicantsassignee.

Formed in the block and communicating with each of the cylinder boresare axially spaced inlet andV exhaust ports. Two swash plates aremounted on the shaft and are provided with different degrees ofinclination. A piston typedistributing valve is reciprocable in each ofthecylinder bores and is arranged with its projecting end in contactwith the swash plate having the smaller degree of inclination. Thesedistributing valve pistons control the flow of liquid through theaxially spaced inlet and exhaust ports and are designed so that theports are closed with zero ylap when the distributing valve pistons areat midstroke. A displacement piston is reciprocable in each cylinderbore and its projecting end is in contact with the other swash plate.The working space defined between Vthe displacement pistons and thepiston valves is connected alternately with an exhaust or an inlet port.The change-over between connection to an inlet or an exhaust port occursas the piston valve passes through v,

the zero lap position dened above. .4

According to the Huber patent the two swash plates were arranged so thatthe high point of one cam was removed substantially 90 from the highpoint of the other cam. If this phase relationship between the camsexists it may be small, does make up a measurable part of the totaldisplacement ofV the -engine andtherefore the timf ing resulting fromthis phase relationship is not entirely correct. This inherentlyincorrect timing was recognized by the patentee.

l'atented Feb. 2, 1960 fi lCe period anti whose amplitude at any pointis equal to the algebraic sum of the amplitudes of the two which it isthe resultant.

The ideal condition involving the displacement of fluid from eachworking space in the present engine is achieved if port reversal occurswhenthe displacement from the working space is zero. Therefore it isdesirable that the zero lap condition,-occurring at midstroke of thedistributing valve pistons, occur when this displacement is zero. Thiscondition isrealizedjwhen the sine wave representing the displacementfrom the working space is precisely 90 out of phase with the sine waverepresenting the motion of the distributing valve piston. This resultcan be achieved by changing the phase relationship between the two swashplates. If this phase angle is made greater than 90, improved valvetiming results. The amount of increase in the phase angle between thetwo swash plates is dependent upon the amplitude of motion of thedistributing valve pistons and the displacement pistons. Of course themotion Vof the valve pistons must be adequate to assure an adequate flowof liquid to and from the Working space at all times during operation ofthe engine, but this motion should be reduced to a practicable minimum.The ideal condition would occur if the two swash plates could bearranged 90 out of phase with one another and still preserveproper'valve action. Unfortunately this condition cannot be achievedbecause the Vdistributing valves must move in order to perform theirfunction and this. motion contributes'to the displacement of liquid inthe engine.

In the illustrated embodiment of the invention, the distributing valvepistons have a displacement which is slightly less than 1/3 of thedisplacement of the displacing pistons. Under these conditions, idealvalve timing is achieved by providing a phase angle of approximately1081/2" between the high points of the two swash plates. This timing iscorrect regardless of the direction of rotation of the swash plates.

A clearer understanding of the invention will be had by reference to thefollowing description which refers to the accompanying drawings inwhich:

Fig. l is an axial section partly in elevation of a motor embodying theinvention.

Fig. 2 is a graphic representation of the displacement characteristic ofthe. motor of thepresentV invention and alsoV showing in dotted line agraphic representation, of a motor. having the characteristic of theabove-mentioned Huber patent, p y

As shown in Fig. l the motor comprises a housing comprising a generallycylindricalV central .portion 11 closed at its opposite ends byscrew-threaded abutments l2 and 13. The abutment l2, Ais provided with acentral sine waves of aperture through which one endof the Vshaftassembly Since the Huber engine is a reversible engine, it was j 1;

necessary that the valves be'timed as nearly correctly as possible forboth directions of rotation and the 90,phase relationship, though acompromise, was believed to represent the best timing available.

The present `invention involves the recognition of the le projects. Thisend of the shaft assembly 14. is .counterbored and the counterboreisprovided with splines whereby theA assembly may be attached to adriving means.

TheY shaft assembly 14 includes a central shaft i5.V which .extendszendto end through thehousingfand Va swash-.plate v16 Yformedintegrallyrwith the shaft 15. Swash plate 16'is Vprovided with aninclined thrust face 17. Projecting normal to the thrust face 17 is acylindrical abutment 18 which sustains the cage of a roller thrustbearing assembly 19. A wear plate 21, parallel with the thrust face 17,is sustained Iby the bearing assembl 19.

)A second swash plate 22 is releasably attached to the opposite end ofthe shaft 15. This swash plate 22 is provided with a thrust faceinclined to the axis of the shaft 15 but at an angle less than the angleof inclination of the thrust face 17 of the swash plate 16. An annularwear plate 24 is mounted parallel to this thrust face and sustained byroller thrust bearing assembly 2S. The bearing assemblies 19 and 25 arefully described and claimed in the Huber application Serial No. 573,420,

iiled March 23, 1956, and assigned to applicants assignee.

A cylindrical cylinder block 26 is pressed into the housing 11 betweenthe swash plates 16 and 22. Cylinder block 2.6 has a central aperture inwhich is mounted a bearing bushing 20V in which the shatt 15 isjournalled. A circular series of open-ended cylinder'bores 27 isprovided in the cylinder block 26. Each of the bores 27 is encircled byspaced annular grooves 28 and 29. The cylinder block 26 is encircled bytwo annular chambers 31 and 32 formed in the housing 11. The annularchambers 31 and 32 are in communication respective with each of theannular grooves 28 and 29 by means of drilled passageways as shown.

A distributing valve 33 of the piston type closes one end of each bore27. The projecting ends of the distributing Valves 33 are encircled bysprings 34 which bias the outer ends of the distributing valves intothrust engagement with the wear plate 24.

A counterbore 35 is provided in each of the distributing valves. Each ofthe distributing valves 33 is provided with an encircling groove 36which is in communication with the counterbore 35 by means of drilledcross ports 37.

The opposite end of each of the bores 27 is closed by a displacementpiston 38. The projecting ends of the pistons 38 are in thrustengagement with the wear plate 21. The piston valves 33 and thedisplacement pistons 38 dene a Working space 27 between them.

A plurality of axial grooves 40 are formed in shaft bearing bushing 20.In this Way iluid may flow vfrom the swash-plate chamber 39 to thesWash-plate chamber 41. The chamber 39 is in one-way flow communicationwith the encircling chamber 31, a check valve 42 being arranged toprevent How from the chamber 31 to the chamber 39. Similarly one-Wayflow communication is alforded from the chamber 41 to theencirclingchamber 29. A check valve 43 inhibits reverse flow throughthis communication.

An oil seal encircles the projecting end of the shaft assembly andcomprises an axially movable sealing member 44 which is biased insealing engagement with swash plate 16 by the combined sealing ring andgarter spring assembly 45.

Solely for the purpose of describing the operation of the device it willbe assumed that the liquid is admitted through chamber 32 so that themotor rotates in the direction of the arrow on the swash plate 22.Liquid is discharged from the engine through chamber 31. For purposes ofsimplifying the illustration it has been illustrated as though the motorincluded an even number of cylinder bores and only two setsofdistributing valves that the upper piston valve 33, as shown in Fig. lis moving to the left as shown by .the arrow and port reversal has notyet occurred. The lower piston valve 33 is moving to the right and portreversal has not yet occurred. The upper working space 27 will beconnected to the discharge chamber 31 while the lower space 27 isconnected to high pressure chamber 32. Port reversal will occur when theswash plates have rotated an additional 181/2 from the positionillustrated in Fig. 1. At this time the distance between the pistons,which is a function of the volume of the Working space 27' will haveachieved its maximum in the lower bore and its minimum in the upperbore. Since the pressure fluid is a liquid and substantiallyincompressible except for included gases it is desirable that the portreversal occur when the direction of displacement changes.

The phase relationship disclosed in the Huber patent causes portreversal to occur too soon in one direction of rotation and too late inthe other direction of rotation. Early port reversal means that aworking space, whose volume is still increasing, is connected to themotors discharge. A partial vacuum will be drawn in this working spaceand will cause the displacement piston to be separated from its swashplate momentarily until the volume of the working space starts todecrease. Reengagement between the swash plate and the displacementpistons occurs with an undesirable impact. In a Working space whosevolume is decreasing, the early port reversal results in the earlyconnection to inlet pressure, which acts in Opposition to the rotationof the motor. In the other direction of rotation, late port reversalresults in the momentary creation of a partial vacuum in the workingspace whose volume is starting to increase, which results in a momentaryseparation of the displacement piston from its swash plate and theimpact resulting from its reengagement. Late port reversal in a workingspace which has started to decrease means that inlet pressure acts inopposition to the motors rotation. Precise timing as taught by thisinvention avoids both of these conditions.

The graphic presentation of Fig. 2 permits a more readily understooddiscussion. The curve DP represents the motion of a single displacementpiston, 4the curve VP represents the motion of the corresponding pistontype distributing valve. The curve ED represents the distance betweenthe pistons. So long as this distance is increasing, the working spaceis receiving liquid and when it is decreasing, liquid is being displacedfrom the Working space.

The points A and B on curve VP represent the points at which portreversal occurs. The curve ED is a curve which is the algebraic sum ofthe curves VP and DP. The curve ED under ideal conditions is 90 out ofphase with the curve VP so that port reversal points, A and B, occurWhen ED has reached its maximum or its minimum. The phase relationbetween VP and DP is selected so that the proper phase relationship isachieved between VP and ED. The dotted curve DP represents motion of adisplacement piston which is 90 out of phase with the curve VP. Thedotted curve ED represents the piston separation which results from thisphase relationship between DP' and VP. Since port reversal occurs at Aand B, it will be apparent that it does not coincide with the points ofmaximum and minimum distance between the pistons. This is the conditioncharacteristic of the Huber device, and the improvement achieved by thepresent invention is easily recognized by comparison of the two sets ofcurves.

Mathematically the solution may be stated:

6' is the phase angle betweenV theA motion of the Valve pistons and thedisplacement pistons.

T is the total displacement of the valve piston. D is the totaldisplacement of the displacement piston.

The phase angle Will be correct regardless of Whether liquid is suppliedto the motor from chamber 32, as assumed in the description of operationor whether it is admitted at 31 to cause rotation in the oppositedirection.

While the invention has been described as it is ernbodied in a motor, itwill be obvious to one skilled in this art that it could also beembodied in a purnp of the same type. The word engine is used in theappended claims in its generic sense and includes pumps and motors.

What is claimed is:

l. In an expansible chamber engine, the combination of a rotary shaftrotatable in either direction; a plurality of expansible chamber unitseach comprising an openended cylinder having supply and exhaust ports, adisplacement piston closing one end of the cylinder, and a distributingvalve of the piston type closing the other end of the cylinder, wherebyan intervening working space is formed, the piston valve serving toconnect the supply and exhaust ports alternately with the working space;and mechanical connections between the shaft and the displacementpistons and between the shaft and the valve pistons so arranged that thedisplacement pistons and valve pistons are reciprocated substantiallysinusoidally and so that each valve piston is reciprocated 90 out ofphase with the sinusoidal variation of the axial distance between it andthe corresponding displacement piston.

2. In an expansible chamber engine, the combination of a rotary shaftrotatable in either direction; a plurality of expansible chamber unitseach comprising an openended cylinder having supply and exhaust ports, adisplacement piston closing one end of the cylinder, and a distributingvalve of the piston type closing the other end of the cylinder, wherebyan intervening working space is formed, the piston valve serving toconnect the supply and exhaust ports alternately with the working space;and mechanical connections between the shaft and the displacementpistons and between the shaft and the Valve pistons so arranged that thedisplacement pistons and valve pistons are reciprocated substantiallysinusoidally, the motion of the displacement pistons being out of phasewith the motion of the Valve pistons by an angle equal to plus sin*1 -lTin which T represents the total valve piston displacement and Drepresents the total displacement of the displacement pistons.

3. in an expansible chamber engine, the combination of a plurality ofexpansible chamber units each including a working space and two cylinderbores communicating therewith, one of the cylinder bores having spacedsupply and discharge ports, a piston type distributing valvereciprocable in the last-named bore and serving to connect said workingspace alternately with the supply and discharge ports, and adisplacement piston reciprocable in the other cylinder bore; a shaftrotatable in either direction relatively to said units and mechanicalconnections between the shaft and the valve pistons and between theshaft and the displacement pistons so arranged that said displacementpistons and valve pistons are reciprocated substantially sinusoidally,and so that each valve piston is reciprocated 90 out of phase with thesinusoidal variation of the volume of said working space.

References Cited in the tle of this patent UNITED STATES PATENTS

